The art of metal conversion often includes welding steel and stainless steel strips, as well as other types of metal strips, end to end to generate longer spools of metal strips. In addition, it is frequently necessary to join two metal strips together at the intake of processing machinery so that the machinery can operate continuously and so that it is not necessary to rethread a strip through the machinery each time a new strip is processed. In the industry, the leading edge of a new strip is spliced to the trailing end of the last strip so that the strips do not have to always be rethreaded. In this context, it is known from practice to splice the metal strips to one another by welded joints.
Traditionally, the required welds are generated by mechanically sheering the trailing end of one strip and the leading end of the new strip, then welding the ends together using a gas tungsten arc welding (“GTAW”) welding process and device. This process, however, is labor intensive, complex and dependent on the skill of the operator. An even more severe issue is that the GTAW is not able to weld material less than 0.008 inches thick and, even so, often requires multiple attempts before obtaining an acceptable weld. Laser based systems have been used in the past, and have been able to weld down to 0.004 inch thickness, but they are very time consuming and difficult to use due to the criticality of the edge conditioning and alignment of the strips.
In view of the above, there is a need for a laser strip splicing method and apparatus which are used to automatically create high quality welds between two metal strips, generally for the purpose of creating longer spools of strip without the need for complex manual alignment or weld parameter configuration.